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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

The experimental dataset for triethoxy(hexadecyl)silane (CAS 16415-13-7) is not complete. Triethoxy(hexadecyl)silane (CAS 16415-13-7) hydrolyses slowly under neutral conditions in water to the corresponding hydrolysis products hexadecylsilantriol and ethanol. Thus the environmental hazard assessment for the aquatic compartment, including waste water treatment plant, is based on the properties of the parent substance in accordance with REACH guidance for Chemical Safety Assessment R.16 (ECHA, 2016). 
No experimental data on the short or long term toxicity of triethoxy(hexadecyl)silane (CAS 16415-13-7) to aquatic organisms are available. Thus, a read-across to the structurally similar substance hexadecyl(trimethoxy)silane (CAS 16415-12-6) was conducted. Both substances are structurally very similar and share the same silanol hydrolysis product i.e. hexadecylsilanetriol. However, their hydrolytic half-life at neutral pH is different (DT50 at pH7: approx. 8 h (source substance) vs. 58.4 h (target substance)). The other hydrolysis products are ethanol and methanol, respectively. Further information on the read across approach can be found in the attached justification in the respective target entry and in the overall justification for grouping of substances attached in IUCLID Section 13.

Acute toxicity studies evaluating the short-term toxicity of the source substance hexadecyl(trimethoxy)silane (CAS 16415-12-6) to aquatic organisms are available for all three trophic levels. All studies were performed according to international guidelines and GLP standards. No short-term toxic effects were observed towards the tested organisms of all three trophic levels up to the highest tested concentration. Due to the very low water solubility the chronic toxicity of the source substance hexadecyl(trimethoxy)silane to aquatic invertebrates was investigated additionally. No chronic effects on Daphnia magna were recorded. 

Results from the same source substance confirm that no toxic effects to activated sludge microorganisms are anticipated by the target substance. An EC10 (3 h) > 100 mg/L was recorded.